1. Field of the Invention
The invention is in the field of control systems for spinning, rolling, or roll stabilized vehicles, either airborne or submersible, such as spinning projectiles/missiles.
2. Description of the Related Art
In certain military applications, there is a significant need for “smart” projectiles wherein the operator can effectively control the course the projectile takes and the target location that is impacted. Such navigational control requires the ability to impart precise forces to a rapidly spinning projectile with respect to the Earth inertial frame to achieve a desired directional course. Some past devices have used arrays of propulsive outlets, fuels and pyrotechnics to produce the necessary forces for the desired two-dimensional course correction. However, these devices suffer from significant disadvantages, such as the danger of premature explosion, and the shock caused by these devices often leads to imprecise course corrections.
Other prior devices have used braking or damping to slow the rotation of one section relative to another. However this requires sufficient braking force to restrain a section substantially stationary relative to a spinning or rolling fuselage or body. This can result in a heat dissipation problem, among other issues.
There is a need for a method and apparatus for controlling the spin rate of a two-section, spinning projectile that can control the relative speeds of rotation of the two spinning sections, de-spin one section relative to the other, maintain a non-rotational state relative to an Earth inertial reference frame, and have the ability to reorient the projectile to a new non-rotational state position. There is a further need for such a method and apparatus that is compact, efficient, robust, easily scalable, requires little power, and avoids the disadvantages of known devices.